Obama addressed supporters in an email message accompanying the video.

"Today, we are filing papers to launch our 2012 campaign," he wrote. "[E]ven though I'm focused on the job you elected me to do, and the race may not reach full speed for a year or more, the work of laying the foundation for our campaign must start today."

The new video is expected to be accompanied by a Federal Election Commission (FEC) filing some time on Monday, which would provide additional details about the campaign. Obama's public schedule, as of Monday morning, called for no public statements, though he could add some to his agenda.

The news of Obama's launch comes at a high-stakes moment during his third year in office. The president has spent the better part of the last month dealing with protracted fighting between Moammar Gadhafi and rebels in Libya while seeking to strike a budget deal with congressional Republicans that would avert a government shutdown in the U.S.

The filing will give Obama the legal opportunity to begin using the campaign infrastructure his staffers have built behind the scenes, and begin an aggressive fundraising effort that could net him close to $1 billion in donations between now and the fall of next year.

The president's aides have already picked out an office in downtown Chicago to headquarter the campaign, the first outside-the-Beltway base of operations for an incumbent president in decades. Jim Messina, Obama's former deputy chief of staff, will serve as campaign manager, and the campaign has hired two deputy campaign managers: Jen O'Malley Dillon, the former executive director of the Democratic National Committee, and Julianna Smoot, the president's former social secretary.

Obama's decision to file in early April places him at the beginning of a new month and a new quarter in the fundraising cycle, giving him time to build in an impressive initial haul from donors. Both Obama and Biden have met in recent weeks with supporters at events billed as non-fundraisers that have hosted a number of top donors whose financial support is likely to come quickly to the campaign. On top of that, the president has a major fundraiser scheduled for mid-April in Chicago, which could bring in millions for his campaign.

The reelection launch comes at an earlier point in his presidency than did the launch of former President George W. Bush's reelection effort, which was announced in mid-May of 2003.

Obama's reelection also precedes many Republicans' official efforts to unseat him.

Few Republicans have formally entered the race: former Minnesota Gov. Tim Pawlenty (R), former Godfather's Pizza CEO Herman Cain and former Louisiana Gov. Buddy Roemer are the only recognized GOP candidates to have filed paperwork to set up a campaign or exploratory committee with the FEC.

A greater number of possible Republican presidential candidates are sitting on the sidelines, only to flirt (with varying degrees of seriousness) with running.

Polls of the Republican field have consistently shown former Arkansas Gov. Mike Huckabee, former Massachusetts Gov. Mitt Romney and former Alaska Gov. Sarah Palin huddled toward the top of the race to win the GOP nomination in 2012, though none of them have actually entered the race and those same polls show no commanding lead for any of them.

Pawlenty's exploratory committee released a Web video Monday highlighting the uncertain economy and claiming Obama lacks the right policies to right the ship.

"I got a question of you: How can America win the future when we're losing the present?" Pawlenty said, in a jab at one of Obama's main talking points. "In order for America to take a new direction, it's going to take a new president."

The Republican National Committee, meanwhile, used Obama's reelection announcement for a fundraising pitch, asking supporters to help the committee raise "$270,000 in the next 72 hours — $1,000 for every electoral vote required to elect the next Republican president."

Polls testing Obama against generic Republican candidates or any of the would-be GOP contenders suggest that Obama, like many incumbent presidents, starts the campaign with an early advantage over his would-be challenger.

That advantage is almost certain to winnow as the 2012 campaign reaches full-swing next year and voters start to pay more attention, and familiarize themselves with the Republican nominee.

Regardless, political analysts have said Obama has positioned himself well for another run, shaking off what he called the "shellacking" of the 2010 midterm elections.

A Gallup poll on Sunday showed him with a 46 percent approval rating; the same percentage of respondents said they disapproved.

Perhaps the biggest variable facing Obama is the state of the economy next fall. Polls of voters repeatedly rank the economy and employment as top concerns going into the election, and dissatisfaction with the pace of the recovery drove Republican victories in the 2010 midterm elections.

Obama got some good news last Friday, when March jobless numbers showed a downward tick in the unemployment rate to 8.8 percent, and an addition in 216,000 nonfarm jobs. But the unemployment rate still remains above where the White House projected it would be at this point when it sold its 2009 stimulus, a signature accomplishment of Obama's first year in office.

Mindful of the primacy of the economy's role in the election, Obama said on Friday that jobs drive his thinking and policymaking decisions on a daily basis.

"You should know that keeping the economy going and making sure jobs are available is the first thing I think about when I wake up the morning; it’s the last thing I think about when I go to bed each night," he said at an event in Landover, Md.